Thermostat "No Power-e298" Despite No Changes in HVAC hardware

[Dantepd82]

MIdday yesterday, our Nest Thermostat began displaying "No Power-e298." We've swapped out the batteries, checked the wiring, checked the fuses, and the HVAC and there appears to have been no changes in any of those. We've gone through all of the troubleshooting stuff we could find, but none of it helped and I absolutely do not have the $125 to get a pro to come out and look at it (And they wouldn't even be available to come until Monday.)

We live in South Florida, where as I type this, it's 103 outside, so getting the AC running again is kind of a big deal.

Any help or guidance would be greatly appreciated.

[Barvic]

Having the exact same problem.  Can’t find any information or solutions. 

[Greenehouse]

I have 2 with the exact same issue.  So this is not a battery issue. It's a software/hardware issue that NEST needs to fix.

[GBD]

First thing I'd check is your AC units condensate drain. Many units will remove power to the thermostat if there is an issue with their float/sensor indicating a backup of water in the drain.

[Dantepd82]

I've checked every physical aspect of the system, nothing's wrong.

[GBD · Accepted solution]

If you have a multimeter handy, check for approximately 24VAC between your RC wire and C wire. If there is no wire on RC, use RH and C. If there is power present, you most likely have a problem with the thermostat or it's backplate. If there is no power, the problem is with your AC system not providing power to the thermostat.

[Ssdungeon]

I shared a not so nice message to you when you were only trying to help.  For that I do apologize and thank you. I had to come back on here and say this.  I hope you have a wonderful day.

[GBD]

No worries, you have yourself a great day as well.